I rented a copy of National Geographic's "Search for PT-109" from Netflix.  I was hoping for some color evidence of a 103 class PT's in the South Pacific.  Sure enough near the begining of the film is what looks like a 103 class Elco in color!  I looked at it over and over and compared it to the black & white photos I had.  It looks right to me and the best evidence I've seen for paint color on these boats.  The best way for me to describe the color is dark olive drab.  If the copyright gods don't mind I'm going to try and snag a screen shot from the film and post it later today.  I'm pretty excited about this find.  If anyone has seen the film and has any comments I'd like hearing from you before I mix the paint. 

Dave